Counterbalanced housing



Mal'd'l 9, 1965 H. A. BORG 3,172,632

COUNTERBALANCED HOUSING Filed April 5, 1963 2 Sheets-Sheet l IN V EN TOR.

HENRY A. 30H6. BY

@JWM

A TTORNEY March 9, 1965 H. A. Bone COUNTERBALANCED HOUSING 2 Sheets-Sheet 2 `Filed April 5. 1963 United States Patent Oiitice 3,172,632 Patented Mar. 9, 1965 3,172,632 CGUNTERBALAN CED HOUSING Henry A. Borg, Romeo, Mich., assigner to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Apr. 3, 1963, Ser. No. 270,307 6 Claims. (Cl. 248-201) This invention relates to suspensions for housings which are pivotally mounted in a cabinet-like structure. More particularly, this invention is directed to a counterbalanced housing for electronic components, which is pivotally mounted for movement from a closed vertical position to an open horizontal position, wherein the internal surface of the closed vertical position becomes the upper surface of the open horizontal position.

Many of the present day computer systems contain numerous groups or packages of modular components mounted into various types of supports or housings, such as, drawers, trays, shelves, and racks. Because of the overall design criteria of certain computer systems, it has been found advisable to house the packages of modular components near the iioor level of the supporting cabinet structures.

It is conventional for individual modular components, such as printed circuit panels to be easily insertable into one side of a housing which can accommodate the numerous panels which make up a modular package, and for the wiring between the panels and the remainder of the computer system to be secured to the opposite side of the housing. For proper maintenance of the modular packages, both sides of the housing should be easily accessible.

Since the packages are mounted near the lioor, a slidable drawer-like support would not be desirable, since access to even one side of the drawer necessitates sliding out of the drawer, and especially, assuming normal orientation, since access to the side adjacent the floor would be extremely limited.

A more desirable mounting for modular packages would be a pivotally suspended housing which would hang vertically in the closed position and thereby aiford continuous access to and heat dissipation from one side of the package, preferably the one exposing the modular panels, and in the open position lie substantially horizontally and sumciently above the floor level to permit easy access to both sides of the modular package.

Due to the weight of a modular package and the fragility of the electronic components mounted therein, it is important that there be no jarring during the translation of the housing to and from the open position. It is, therefore, also desirable that the mounting for the housing provide a type of counterbalancing of damping which is not only adjustable to the weight of the housing, but also varies proportionately with the reactive force of the housing as the housing translates.

Accordingly, it is one object of this invention to provide a pivotable cabinetry suspension which enables a housing to be translated ninety degrees while being simultaneously elevated such that its inner face becomes its upper face.

Another object of this invention is to increase the accessibility to -both faces of a housing assembly.

Still another object of this invention is to provide a counterbalance for a pivotally mounted housing wherein the force of the counterbalance increases and decreases proportionate to the reactive force of the housing.

A still further object of this invention is to improve counterbalancing means for a pivotally mounted housing wherein the force of the counterbalance is adjustable according to the weight of the housing and automatically varies with increases and decreases in the reactive force of the housing.

The housing of this invention is pivoted on a supporting structure by upper and lower pairs of links, whereby the housing is pivotable from a closed vertical position to an open horizontal position by an upward and outward movement of the housing. The ends of the upper links adjacent the supporting structure have eccentric surfaces over which pass spring-biased cables for compensating counterbalancing the changing reactive force of the pivot housing.

Other features and objects of this invention will become apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the embodied invention shown in a partly open position;

FIG. 2 is a side elevational View of the invention in the closed position;

FIG. 3 is a side elevational view of the invention in the open position;

FIGS. 4 and 5 are force diagrams of the cam arms of this invention in the positions shown in FIGS. 2 and 3, respectively.

ln the preferred embodiment of this invention, as illustrated in FIGS. 1-3, there is shown a portion of a cabinet 11 having a transverse top member 13 and a base plate 15. Secured between the top 13 and base 15 are a plurality of Vertical side frames 17, two of which are shown. This top, base, and each pair of sides deine a rectangular area into which a support in the form of a rectangular housing 19 is pivotally mounted.

The housing 19, as best seen in FIG. 1, comprises the side members 21, the end 23, and the front 25 having a handle 27. Other members, not shown, may be employed for rigidity of the cabinet and housing.

The housing 19, as illustrated, is a rack in which printed circuit panels or other types of modules 29 are mounted. The modules 29 are inserted in the lower face 31 of the rack forming several rows and columns, and are accessible therefrom. The wiring and associated hardware 33 intercoupling the modules and connecting the modular package with the remainder of the computer are laced and mounted in the upper face 35 of the rack and are easily accessible therefrom.

As herein used, the terms forward and lower will refer to the face 31 of the rack into which the modules 29 are inserted and secured, as well as those portions of the cabinet 11 adjacent that face of the rack. The terms rearward and upper will be used in reference to the face 3S `of the rack in which the wiring is located, as well as those portions of the cabinet adjacent that face of the rack. As is apparent from the drawings, the forward and rearward faces of the housing in the vertical position become respectively, the lower and upper faces in the horizontal position. Although a rectangular rack is employed in this preferred embodiment, other types of supporting means could be used.

Secured to each side 21 of the rack are pivots 37 and 39. Each pivot 37 is slightly below the midportion of the side and adjacent the lower face 31. Each pivot 39 is near the end 23 and also adjacent the lower face 31. Stop studs 41 and 43 are also mounted onto each of the racks sides and are positioned near the lower face 31 and between the pivots 37 and 39. The utility of these elements will become apparent hereinafter.

Fixed on each side frame 17, near its midpoint, is a rearwardly extending bracket 45 having a pivot 47. A pair of braces or links 49 is mounted in parallel one onto each side of the rack 19 between the brackets 45 i and the rack sides 21. Each brace 49 is fastened at one of its ends to the pivot 47 on a bracket 45 and at its other end to .the pivot 39 near the end of the rack side 21 aligned with that bracket. Mounted in this manner, the brace/491 can swing such that it will carry the pivot 39 `alon an er arc of at least 90, as shown by the arc line 51 in FIG. 3 having a swing of slightly over 100, and thereby support its associated rack portion during its translation from the vertical position of FIG. 2 to its substantially horizonal position of FIG. 3.

Mounted toward the top of each side frame 17 is a pivot 53. A pair of arms 55 are mounted in parallel on the rack sides 21 with one end of each arm fastened to a pivot 37 on the rack side and the other end fastenedd to a pivot S3, thus forming a second pair of links. Mounted in this manner, each arm 55 can swing such that it will carry the pivot 37 less than 90 along the arc line 57, shown in FIG. 3 as having a swing of about 65, and thereby cause its associated modular portion to follow that path when it is translated from the vertical to the horizontal position.

As seen in FIG. 2, the pivots 53, 37, and 35 all lie on a common line when the rack is in its vertical or closed position, thus alleviating stress along the various cabinet members.

Also mounted on each side frame 17 is a cable pulley 59 which is adjacent to and aligned with a respective pivot 53, and thereby acts as an extension of its associated arm 55. An eccentric surface 61 is formed integral with the upper end of each arm 55 proximate the pivot 53. A keeper plate 63 is mounted on each side of each eccentric surface.

An individual cable 65 is secured to the upper face of each of the arms 55 by suitable means 67. Each cable 65 passes over an eccentric surface 61 between keeper plates 63 and over a pulley 59 down toward the base plate 15 rearward of its respective side frame 17.

An anchor 69 is fixed to the base plate 15 behind each side frame 17 and an adjustable eyebolt 71 is mounted in each anchor. A counterbalance spring 73 is secured between each eye bolt and the end of its associated cable 65.

A lock pin 75 is xed in each arm 55 near its midpoint and extends toward its associated rack side 21. A lock 77 is mounted on each of the rack sides near the front 25 and adjacent the lower face 31. The lock 77 contains an vopposing pair of bowed leaf springs 7,9 which dene a channel for the insertion therebetween of the lock pin 75. At the midpoint of each leaf spring is a concavity .which forms a detent for the lock pin. As shown in FIG. 2, the lock pin will seat in the lock when the rack is translated into the closed vertical position. The necessity for a Vlocking device will be discussed hereinafter.

It will now be apparent to those skilled in the art that, due to the effect of the eccentric surface 61, the distance along a cable 65 between an eye bolt 71 and the cable securing means 67 will be greater when the rack 19 is in the vertical position than the cable distance between the same points when the rack is in its horizontal position.

Assuming that the counterbalance spring 73 is under slight tension when the rack is horizontal, it will be under greater tension when the rack is vertical. Hence, the counterbalance spring 73 will tend to urge the rack v from the closed to the open position thus allowing an Y operator desiring to open the rack for access to the wired Yupper surface 35 to exert far less effort than if the VVcounterbalance effect were not present. The weight of Yarack assembly containing numerous modules and their associated hardware and wiring could easily exceed thirty unds, thus counterbalancing is a desirable asset. Since kgisurged out from its closed position, the abovei described lock 77, or its equivalent, is necessary to hold the rack vertical.

fmovefthe Vmodular rack assembly from the closed en position, all that an operator need do is handle 27 and pull it outwardly to free the between the springs 79 of the lock 77.

'u rd, motion of the handle will overcome tlc :inertiaV o @the vertically hanging rack suiiiciently for the counterbalance spring 73 to elevate and pivot the rack into the open position. The arc line 81, shown in FIG. 3, illustrates the path that the handle 27 follows during the translation of the rack.

The arms 55 will be unable to pivot upward above the position shown in FIG. 3 due to the fact that the pivots 37 and 39 are a'iixed distance apart and that, if there were an attempt to further elevate the arms, there would be an impossible divergence between the arcs 51 and 57. This bulit-in limitation acts as a safeguard in that the rack, as it nears the open position, is only rotating about the pivots 37 and 39. Were it also'dropping down from an over-elevation, a sudden stop at the open position might cause an excessive shock. to the delicate electrical components in the modular package.

Hereinbefore the terms open and horizontal have been used interchangeably with reference to the position that the supporting assembly assumes when its upper face 35 is easily accessible. As shown in FIG. 3, the rack has been pivoted slightly past the horizontal level so that its front Y25 is a little lower than its end 23. In this position portions of the upper face 35 are even more accessible to a maintenance engineer standing parallel to the front 25.

The stop studs 41 mounted on the rack sides 21 are each slidably fastened in an arcuate slot 83 and may be tightened in any position along the slot by conventional means, not shown. In the open position the arms 55 will abut the studs 41 and thereby hold the rack from further forward movement. Prior adjustment of the studs position will determine the extent of the forward movement.

Although the effect of the counterbalance spring 73 will be at a minimum in the open position, the Weight of 'the front end of the rack assembly upon the pivots 37,

coupled with static inertia, will be sufficient to insure stability and prevent any tendency for the rack to move rearward from the open position.

To close the housing assembly, the operator lifts up on the handle 27 until it passes the apex'of the arc 81, thereafter a gentle continuous rearward urging will cause the rack to move easily toward the closed position. As the rack assembly translates closer to the vertical position the designed resistance due to counterbalance spring 73 will continuously increase and always be slightly greater than the downward force on the rack assembly due to gravity. This over-counterbalanced effect is another built-in safeguard and will prevent the rack from suddenly droppingrinto the closed position and damaging the modules if the operator were to unexpectedly release the handle 27. In `the closed position, as shown in FIG. 2, the stop studs 43 will abut the braces 49 to preven the rack from swinging further rearwardly.

As above discussed, the preferred embodiment of this invention is equipped with o-ver-counterbalancing means which, by exerting continuous upward force just greater than the reactive force of ther-ack, permits the rack to be translated easily into the open position and to be again closed easily and safely.

An examination of the force diagrams, FIGS. 4 and 5, will readily demonstrate the mechanics involved wherein:

F1 represents the force of a spring 73 acting through a cable 65 over an eccentric surface 61.

F2 represents the reactive force of the supporting assembly.

H represents the height of the acting portion, or moment arm, of the eccentric surface above a line joining the pivots 37 and 53.

X represents the distance between the pivots 37 and 53 and hence the length of the arm 55.

F1 H equals the force of each of the two spring loaded cables times the eccentrics height at a specific arm rotation above the pivot 53.

FZXX equals the reactive force of the supporting assembly for a specific arm rotation times the arm length.

Although F1 H and F2 X are continuously changing as the arm 575 moves along the are line 57, both decrease proportionately as the rack assembly translates toward the open position. Were a continuous state of equilibrium desired, a balanced equation would be However, since the rack assembly is to be overcounterbalanced, the proper equation is:

As previously mentioned, the eye bolt 71 is adjustable. The tension of the counterbalance spring 73 may thus be increased or decreased to accommodate for different weights of a housing 19. It should also be noted that the shape and size of the eccentric surface 61 will depend on the size and to some extent the Weight of the housing 19.

Hereinabove has been described a novel translatable supporting assembly having two pairs of pivotal arms of links which are so mounted with respect to a rack and a cabinet structure that the rack can be translated from a closed vertical position, in which a first face of the rack is accessible from the front, to an open, substantially horizontal position, in which a second face of the rack is accessible from above while the rst face is now accessible from below. There also has been described a counterbalancing means which, due to the fact that a continuous over-counterbalanced condition is maintained, enables the housing to be easily and safely translated to and from the closed position.

Although only one supporting assembly has been discussed, it should be obvious that a plurality of them could be suspended side by side in the same cabinet with a side frame between each rack.

It would be possible, in certain applications where weight was not a compelling factor, to eliminate the braces 49, their associated pivots 37 and 47, and the brackets 45. The omission of the braces would require the operator to apply sufficient guidance to cause the housing to rotate about the pivots 37 to attain the horizontal position, but once so positioned the housing would be stable for the same reasons as presented hereinabove.

The inventive structure could also be modified by removing the pulley 59 and extending the eccentric surface 61 into the area previously occupied by the pulley, but not changing the location of the pivot 53. This elimination of the pulley will, however, yrequire addition of clearance room for the end of the eccentric surface which now extends rearward of .the pivot 53.

Another possible modification would lie in moving the pivots 37 and 39 upward along the rack sides 21 to slightly below the sides midpoint, while still maintaining the vertical alignment of the pivots 37, 39, and 53 in the assemblys closed position. So modified, the end of the brace 49, extending slightly forward of the pivot 39, will impinge against a lower portion of the arm 55 when the rack assembly is in the open position, thus increasing the racks stability and obviating the need for the stop studs 41, unless adjustability near the horizontal position and above the stop position provided by the brace were also desired.

The embodiments of this invention have, by way of example, been described as supporting assemblies for retaining electronic modules. However, it should now be apparent to those skilled in the art that this novel counterbalanced suspension linkage could be employed in other types of cabinetry and mounting apparatus far removed from the field of electronics to provide in one position easy access to a -rst face of the housing and in another position ready access to a second face of the housing as well as reasonable access to the first face.

Additional changes and substitutions in the form and details of this invention could also be made by those skilled in the art without departing from its fundamental novel features.

What is claimed is:

1. In a linkage for pivotally mounting' a' counterbalfanced rectangular support in a vertical frame wherein said support has a substantially horizontal position and a vertical position, a pair of parallel links each having one end pivoted to a respective side of the support and the other end pivoted to the frame, the frame pivots being higher than the support pivots in either position of the support, a flexible band associated with each of said links, said band being attached to its associated link intermediate said pivot points and having a rst portion passing from said attachment upwardly to a point above and beyond said frame pivot and a second portion extending downwardly beyond said point, resilient, counterbalancing means attached between the downwardly extending ends of each of said bands and said frame, and eccentric means on the surface of each of said links contacting said first portions of said individual bands for varying the effective moment arm of said first portion as said support is translated from one of its two positions to the other, whereby the force of said counterbalancng means is increased as said support is translated from its horizontal to its vertical position.

2. The linkage set forth in claim 1 including a pulley mounted on said frame above each of said frame pivots for guiding from beneath said associated exible band intermediate said first and second portions thereof.

3. The linkage set forth in claim 1 wherein said eccentric means for Varying the effective moment arm of said first portion continuously maintain the force exerted by said counterbalancing means greater than the reactive force of said support during translation from the horizontal to the vertical position, and said resilient, counterbalancing means is adjustably pretensioned.

4. The linkage set forth in claim 1 including a pair of parallel braces each having one end pivoted to a side of said support and vertically aligned with and beneath the pivots of said pair of links when said support is vertical, and having the other end pivoted to said frame, said frame pivots of said braces being higher than said support pivots of said braces when said support is vertical, but lower than said brace support pivots when said support is substantially horizontal.

5. A counterbalanced support pivotally mounted in a frame for movement between a closed vertical position and an open, substantially horizontal position comprising a pair of parallel links, each having one end pivoted to a respective side of said support and the other end pivoted to said frame, a pair of biased flexible bands respectively attached to each of said links inwardly from said frame pivots and passing over said ends of said links pivoted to said frame in the direction of said bias and eccentric means on the surface of each of said links cooperating with said liexible bands for varying the effective moment arm of each of said bands as said housing is moved between said positions.

6. Counterbalancing linkage for mounting a rectangular support in a frame wherein the support is translatable between a vertical position in the frame and a substantially horizontal position outstanding from the frame, and the rearward face of the support in the vertical position is the upper face in the horizontal position comprising a pair of parallel links each having one end pivoted to a respective side of said support and the other end pivoted to said frame, said frame pivot being higher than said support pivot when said support is in either of said positions, a pair of parallel braces each having one end pivoted to a respective side of said support and vertically aligned with and beneath the pivots of said pair of links when said support is vertical and having the other end pivoted to said frame, a pair of flexible, inelastic bands, one associated with each of said parallel links, each of said bands being attached to its associated link intermediate the ends of said link and extending upwardly to a point above and beyond said frame pivot of said link and uw then downwardly, resilient over-counterbalancing means attached to the downwardly extending ends of each of Said bands, and eccentric means o n each of said pair of parallel links in contact with said associated bands for v arying the length of the effective moment arm of the upwardly extending portion of each band as said support is translated between said positions and for increasing theV force of said over-counterbalancing means as said support is translated from said horizontal to said vertical position.

References Cited in the le of this patent UNITED STATES PATENTS Erret Mar. 27, 1917 Wasmuth T Oct. 22, 1929 Rouverol Feb. 9, 1960 Peck Oct. 23, 1962 FOREIGN PATENTS France Feb. 28, 1927 

1. IN A LINKAGE FOR PIVOTALLY MOUNTING A COUNTERBALANCED RECTANGULAR SUPPORT IN A VERTICAL FRAME WHEREIN SAID SUPPORT HAS A SUBSTANTIALLY HORIZONTAL POSITION AND A VERTICAL POSITION, A PAIR OF PARALLEL LINKS EACH HAVING ONE END PIVOTED TO A RESPECTIVE SIDE OF THE SUPPORT AND THE OTHER END PIVOTED TO THE FRAME, THE FRAME PIVOTS BEING HIGHER THAN THE SUPPORT PIVOTS IN EITHER POSITION OF THE SUPPORT, A FLEXIBLE BAND ASSOCIATED WITH EACH OF SAID LINKS, SAID BAND BEING ATTACHED TO ITS ASSOCIATED LINK INTERMEDIATE SAID PIVOT POINTS AND HAVING A FIRST PORTION PASSING FROM SAID ATTACHMENT UPWARDLY TO A POINT ABOVE AND BEYOND SAID FRAME PIVOT AND A SECOND PORTION EXTENDING DOWNWARDLY BEYOND SAID POINT, RESILIENT, COUNTERBALANCING MEANS ATTACHED BETWEEN THE DOWNWARDLY EXTENDING ENDS OF EACH OF SAID BANDS AND SAID FRAME, AND ECCENTRIC MEANS ON THE SURFACE OF EACH OF SAID LINKS CONTACTING SAID FIRST PORTIONS OF SAID INDIVIDUAL BANDS FOR VARYING THE EFFECTIVE MOMENT ARM OF SAID FIRST PORTION AS SAID SUPPORT IS TRANSLATED FROM ONE OF ITS TWO POSITIONS TO THE OTHER, WHEREBY THE FORCE OF SAID COUNTERBALANCING MEANS IS INCREASED AS SAID SUPPORT IS TRANSLATED FROM ITS HORIZONTAL TO ITS VERTICAL POSITION. 